﻿Stannic 
  chloride, 
  

  

  J5 
  

  

  = 
  -■67 
  

  

  /i-Pentane, 
  

  

  ?5 
  

  

  = 
  -•19 
  

  

  /^-Octane, 
  

  

  J? 
  

  

  = 
  -•83 
  

  

  Di-isobutyl, 
  

  

  5? 
  

  

  = 
  -•55 
  

  

  Benzene, 
  

  

  ?5 
  

  

  = 
  -•15 
  

  

  relation 
  to 
  Pressure 
  and 
  Temperature. 
  211 
  

  

  molecules 
  in 
  configurations 
  of 
  greater 
  density 
  *. 
  This 
  con- 
  

   dition 
  is 
  violated 
  when 
  the 
  equation 
  is 
  applied 
  to 
  volumes 
  of 
  

   a 
  liquid 
  at 
  temperatures 
  much 
  below 
  the 
  critical 
  point 
  where 
  

   the 
  Jimit 
  v=b 
  (or 
  i|r=*3333 
  . 
  . 
  . 
  .) 
  is 
  more 
  nearly 
  approached. 
  

   Taking 
  a 
  few 
  examples 
  : 
  

  

  Carbon 
  tetrachloride, 
  Deviation 
  = 
  — 
  *23 
  when 
  i|r 
  = 
  -3876 
  

  

  ^ 
  = 
  •3678 
  

   ^ 
  = 
  •3885 
  

   ^ 
  = 
  •3826 
  

   ^ 
  = 
  •3864 
  

   ^ 
  = 
  •3870 
  

  

  It 
  must, 
  however, 
  be 
  observed 
  that 
  relatively 
  large 
  de- 
  

   viations 
  are 
  not 
  invariably 
  connected 
  with 
  small 
  values 
  of 
  

   yjr, 
  for 
  we 
  have 
  also 
  

  

  Isopentane, 
  Deviation 
  = 
  — 
  *05 
  when 
  -v/r 
  = 
  *3908 
  

  

  Fluorbenzene, 
  „ 
  =—'08 
  „ 
  i/r 
  = 
  *3805 
  

  

  Whilst, 
  therefore, 
  a 
  diminution 
  in 
  the 
  value 
  of 
  " 
  b 
  " 
  would 
  

   increase 
  the 
  value 
  of 
  3-^ 
  — 
  1, 
  and 
  tend 
  to 
  annul 
  deviations 
  of 
  

   negative 
  sign, 
  it 
  is 
  evident 
  that 
  such 
  variations 
  can 
  only 
  be 
  

   of 
  very 
  small 
  magnitude, 
  for 
  otherwise 
  deviations 
  of 
  positive 
  

   sign 
  would 
  be 
  produced. 
  

  

  As 
  showing 
  the 
  sensitiveness 
  of 
  the 
  invariant 
  function 
  to 
  

   slight 
  changes 
  in 
  volume, 
  one 
  or 
  two 
  numerical 
  examples 
  

   may 
  be 
  given. 
  In 
  Table 
  IV. 
  the 
  values 
  for 
  carbon 
  tetra- 
  

   chloride 
  have 
  been 
  calculated, 
  at 
  temperature 
  intervals 
  of 
  

   20° 
  C, 
  from 
  100° 
  C. 
  to 
  280° 
  C. 
  inclusive. 
  The 
  calculated 
  

   value 
  at 
  a 
  lower 
  temperature, 
  T=90° 
  C, 
  gives 
  % 
  = 
  15*72, 
  

   the 
  volume 
  of 
  unit 
  mass 
  of 
  the 
  liquid 
  being 
  "6971 
  c.c. 
  A 
  

   difference 
  of 
  '01 
  c.c. 
  in 
  excess 
  of 
  this 
  value 
  would 
  make 
  

   2=16*01. 
  The 
  critical 
  volume 
  of 
  unit 
  mass 
  is 
  1*799 
  c.c, 
  

   and 
  a 
  similar 
  result 
  would 
  be 
  produced 
  on 
  reducing 
  this 
  

   value 
  by 
  one 
  and 
  a 
  half 
  per 
  cent. 
  Again, 
  in 
  the 
  case 
  of 
  

   stannic 
  chloride 
  the 
  values 
  of 
  (/> 
  and 
  -\|r 
  have 
  been 
  calculated 
  

   from 
  the 
  critical 
  volume 
  r 
  = 
  1*347 
  c.c. 
  If 
  we 
  take 
  the 
  

   smaller 
  value 
  r 
  = 
  1*325 
  c.c, 
  the 
  following 
  results 
  for 
  the 
  first 
  

   and 
  last 
  lines 
  of 
  the 
  table 
  will 
  be 
  obtained: 
  — 
  

  

  Line 
  (1), 
  2 
  = 
  15'86 
  in 
  place 
  of 
  15*33. 
  

   (10), 
  2= 
  16*10 
  in 
  place 
  of 
  15*94. 
  

  

  * 
  '"There 
  can 
  be 
  no 
  doubt 
  that 
  molecules 
  are 
  not 
  spheres 
  in 
  shape 
  

  

  they 
  are 
  more 
  probably, 
  without 
  exception, 
  flattish 
  discs 
  of 
  very 
  

  

  small 
  thickness." 
  (O. 
  E. 
  Meyer, 
  'Kinetic 
  Theory 
  of 
  Gases.' 
  English 
  

   Translation 
  from 
  2nd 
  Revised 
  Edition 
  by 
  R. 
  E. 
  Baynes, 
  p. 
  323.) 
  

  

  Hence 
  it 
  is 
  open 
  to 
  question 
  how 
  far 
  conclusions 
  based 
  upon 
  the 
  

   hypothesis 
  of 
  the 
  spherical 
  character 
  of 
  molecular 
  action 
  can 
  be 
  pressed 
  

   to 
  the 
  limit 
  when, 
  as 
  in 
  the 
  liquid 
  state, 
  molecules 
  are 
  densely 
  packed, 
  

   however 
  convenient 
  the 
  conception 
  may 
  be 
  from 
  a 
  mathematical 
  point 
  of 
  

   view. 
  

  

  